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Produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a U.S. DOE national laboratory

35th St. Craig Ave. Craig Colucci Pkwy. DART’sDART’s LNGLNG BusBus FleetFleet FinalFinal ResultsResults Alt Blvd. D ALLAS AREA RAPID TRANSIT’S (DART) LNG BUS FLEET: Final Results

Alternative Fuel Transit Bus Evaluation

by

Kevin Chandler, Battelle Paul Norton, National Renewable Energy Laboratory Nigel Clark, West Virginia University

October 2000

The authors wish to acknowledge the help and cooperation of the staff, in particular Rocky Rogers and Darryl Spencer, at the host site, Dallas Area Rapid Transit. The authors also acknowledge the editorial contri- butions of Vincent Brown at Battelle and Stefanie Woodward at NREL.

World Wide Web: http://www.afdc.doe.gov National Alternative Fuels Hotline: 1-800-423-1DOE Notice

This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, com- pleteness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or ser- vice by trade name, trademark, manufacturer, or otherwise does not neces- sarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.

Available electronically at http://www.doe.gov/bridge Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 phone: 865.576.8401 fax: 865.576.5728 email: [email protected]

Available for sale to the public, in paper, from: U.S. Department of Commerce National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 phone: 800.553.6847 fax: 703.605.6900 email: [email protected] online ordering: http://www.ntis.gov/ordering.ht

ii Final Results Alternative Fuel Transit Buses

Table of Contents

Executive Summary ...... v Overview ...... 1 Alternative Fuel Projects at DOE and NREL ...... 2 The Transit Bus Evaluation Project ...... 2 Host Site Profile: Dallas Area Rapid Transit ...... 2 DART’s LNG Buses ...... 3 DART’s Involvement in Air Quality Improvement ...... 5 Project Design and Data Collection ...... 5 DART’s Facilities and Bulk Fuel Storage ...... 7 Project Start-Up at DART ...... 9 LNG Engine Issues ...... 9 Range and Fuel Gauge Issues ...... 9 Other Fueling Issues ...... 10 Evaluation Results ...... 12 Bus Use in Transit Service ...... 12 Average Speed ...... 13 Monthly Miles Driven ...... 13 Fuel Economy, Maintenance, and Costs ...... 14 Fuel Economy ...... 14 Fuel Cost per Gallon ...... 15 Fuel Cost per Mile ...... 15 Engine Oil Consumption and Cost ...... 15 Factors Affecting Maintenance Costs ...... 16 Maintenance Costs by Vehicle System ...... 16 Roadcalls ...... 18 Warranty Costs ...... 18 Overall Maintenance Costs ...... 19 Overall Operating Costs ...... 19 Emissions Testing Results ...... 20 LNG Technology Progress in Transit ...... 22 Roadcalls ...... 23 Maintenance Costs ...... 23 Fuel Economy ...... 24 Emissions Testing Results ...... 24 Summary ...... 25 Summary and Conclusions ...... 26 Future LNG Operations at DART ...... 27 Contacts ...... 28 References and Related Reports ...... 29 Appendix A. Fleet Summary Statistics ...... 31 Appendix B. Emissions Test Results ...... 37 iii iv Methods Data were gathered daily from fuel and maintenance tracking systems for more than 1 year. The data parameters included • Fuel consumption • Mileage and dispatching records • Engine oil additions and oil/filter changes Executive Summary • Preventive maintenance action records In 1998, Dallas Area Rapid Transit • Records of unscheduled maintenance (DART), a public transit agency in Dallas, (such as roadcalls) and warranty repairs Texas, began operating a large fleet of heavy-duty buses powered by liquefied The data collection was designed to natural gas (LNG). As part of a $16 mil- cause as little disruption for DART as lion commitment to alternative fuels, possible. The original evaluation fleets DART operates 139 LNG buses serviced consisted of 10 LNG buses and 5 similar by two new LNG fueling stations. diesel buses. Five additional LNG buses were added to the evaluation after the The U.S. Department of Energy (DOE) Office start-up period. of Heavy Vehicle Technologies sponsored a research project to collect and analyze data Results on the performance and operation costs of Some early start-up issues required 15 of DART’s LNG buses in revenue service, the LNG buses to operate on restricted compared with the performance of 5 diesel routes and schedules, but after these buses operating on comparable routes. issues were resolved, the LNG and diesel fleets performed the work DART Objective expected during the evaluation period. The objective of the DOE research project, managed by the National Renewable Energy The LNG buses emitted less nitrogen Laboratory, was to provide transportation oxides and particulate matter than the professionals with quantitative, unbiased diesel buses. By most other measures of information on the cost, maintenance, oper- operation, the diesel buses performed ational, and emissions characteristics of LNG better than the LNG buses. The LNG as one alternative to conventional diesel buses had lower energy equivalent fuel fuel for heavy-duty transit bus applications. economy, higher fuel costs per mile dri- ven, and higher engine and fuel system In addition, this information should benefit maintenance costs per mile driven than decision makers by providing a real-world the diesel buses. account of the obstacles overcome and the lessons learned in adapting alternative Overall, the operating cost comparison fuel buses to a transit site previously was mixed. The operating costs for designed for diesel buses. It also identi- the original LNG buses averaged about fies technology areas where future 3% higher than for the diesel buses. research and development efforts should The 10 original LNG buses averaged be focused. The field study at DART was $0.799 per mile, and the diesel buses part of DOE’s ongoing Alternative Fuel averaged $0.773, giving the diesel Transit Bus Evaluation Project. buses an advantage of $0.026 per mile.

v Alternative Fuel Final Results Transit Buses

However, the new LNG buses showed wastegate). Some engine problems with the lowest operating cost per mile, the DART LNG buses persisted through at $0.713—about 8% less than the the end of the study period. Design diesel buses. work continues on the LNG buses.

Lessons Learned The original LNG buses were designed with a three-tank system that provided The LNG bus evaluation project provided a range of only 250 miles in service DART, DOE, and other participants the (277 miles in track tests), well below opportunity to learn many lessons about DART’s goal of 400 miles. At DART’s alternative fuels: request, the manufacturer, NovaBUS, • Transit agency employees should learn added a fourth LNG tank, which all they can about potential problems provided an acceptable range of with alternative fuels in field opera- 358 miles in service (380 miles in tions. Agencies should plan for unex- track tests). pected contingencies and exercise patience through the start-up process. Other obstacles overcome included ensuring full tanks at each fueling stop, • Critical vehicle systems should undergo redesigning the LNG fueling nozzle to engineering design validation and/or prevent leaking, exploring the use of a performance tests before vehicles are breakaway hose to prevent damage from put into service. driveaways during fueling, and a starter • Transit agencies need to be committed lockout switch at the fueling door. to success and to invest the personal energy, infrastructure, and financial By spring 2000, DART had resolved resources needed to make alternative nearly all the problems with the LNG fuel programs work. buses by applying the lessons learned • The LNG industry needs to improve its from start-up and by cooperating with own technology support infrastructure, manufacturers and component suppli- and be able to respond to the needs of ers. The LNG buses have operated on large fleets of LNG vehicles. all routes (except a few of the longest) originating from the Northwest facility. • All critical systems need to be inte- grated through strong communication Future LNG Operations at DART and accurate information within the transit agency. DART’s two facilities for fueling and servicing LNG buses have room to Obstacles Overcome grow. New procurements for buses have a provision for LNG buses. DART Early in the deployment of the LNG continues to evaluate the operation of buses, DART experienced problems with its LNG fleet. operating range, fuel mileage, fuel filling, and reliability. DART also resolved prob- DART continues to work on optimizing lems with methane sensors, fire suppres- the LNG bus operations. DART is sion systems, electronics, and multiplex- working with Cummins and ZF (the ing systems. (Some of these problems transmission vendor) to raise the fuel also occurred with the diesel fleet.) economy 5%–10% by optimizing the shift points of the transmission and by Cummins resolved several problems improving engine component design. with early failure of engine components DART is also working to optimize the (e.g., turbocharger, spark plugs, and onboard LNG fuel tank system. vi Final Results Alternative Fuel Transit Buses

Overview What Is LNG Fuel and How Is It Processed? Dallas Area Rapid Transit (DART), a transit agency based in Dallas, Liquefied natural gas is a naturally occurring mixture of hydro- Texas, has been operating lique- carbons (mainly methane, or CH4), that has been purified and fied natural gas (LNG) buses condensed to liquid form by cooling cryogenically to -260°F (-162°C). from its Northwest facility since At atmospheric pressure, it occupies only 1/600 the volume of natural November 1998. The LNG bus gas in vapor form. fleet now includes 139 LNG Methane is the simplest molecule of the fossil fuels and can be buses in service. Between burned very cleanly. It has an octane rating of 130 and excellent February 1999 and January 2000, properties for spark-ignited internal combustion engines. data on DART’s LNG and diesel buses were collected for evalua- Because it must be kept at such cold temperatures, LNG is stored tion as part of the U.S. Depart- in double-wall, vacuum-insulated pressure vessels. Compared to the ment of Energy (DOE)/National fuel tanks required for using compressed natural gas (CNG) in vehicles Renewable Energy Laboratory operating over similar ranges, LNG fuel tanks are smaller and lighter. (NREL) Alternative Fuel Transit However, they are larger, heavier, and more expensive than diesel Bus Evaluation Project. fuel tanks. Compared to conventional fuels, LNG’s flammability is limited. It is The purpose of this report is nontoxic, odorless, noncorrosive, and noncarcinogenic. It presents to provide transportation no threat to soil, surface water, or groundwater. professionals with summary information on the cost, LNG is used primarily for international trade in natural gas and for maintenance, operational, meeting seasonal demands for natural gas. It is produced mainly at and emissions characteristics LNG storage locations operated by natural gas suppliers, and at cryo- of LNG as one alternative to genic extraction plants in gas-producing states. Only a handful of conventional diesel fuel for large-scale liquefaction facilities in the United States provide LNG transit bus applications. The fuel for transportation. report should also benefit This information was adapted from the following Web sites. Each decision makers by providing offers further information about LNG: a real-world account of the obstacles overcome and the – Natural Gas Vehicle Coalition: http://www.ngvc.org/qa.html lessons learned in adapting – Alternative Fuels Data Center: http://www.afdc.doe.gov alternative fuel buses to a site previously geared toward – Zeus Development Corp./LNG Express: diesel buses. It also identifies http://www.lngexpress.com/welcome.htm technology areas where future – CH-IV Cryogenics: http://www.ch-iv.com/lng/lngfact.htm research and development efforts should be focused.

This report summarizes the results of the LNG study at DART. Further technical background, research methods, data, and detailed discussions are pre- sented in a companion document (DART’s LNG Bus Fleet Final Data Report, NREL, June 2000).

1 Alternative Fuel Final Results Transit Buses

Alternative Fuel Projects at Heavy-duty alternative fuel transit DOE and NREL buses have been evaluated through data collection and On behalf of DOE, NREL (a DOE analysis since 1993. The transit national laboratory) managed the bus program includes 15 demon- data collection, analysis, and stration sites and continues to reporting activities for the DART add new sites for further data LNG bus evaluation. collection and evaluation.

NREL and participating companies Sites have been selected accord- across the United States are evalu- ing to the kind of alternative fuel ating several types of alternative technology in use, the types of fuels. These fuels have included buses and engines, the availability LNG, compressed natural gas of diesel comparison (“control”) (CNG), biodiesel, ethanol, vehicles, and the transit agency’s methanol, and propane (liquefied interest in using alternative fuels. petroleum gas). After analysis, peer review, and Alternative One of NREL’s missions is to DOE approval, results from each

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A N Transit Buses C I I new site are published separately. T R E D E M ST A AT ES OF Produced for the nomics of alternative fuel vehicles U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL), a U.S. DOE national laboratory (AFVs) objectively so that • Fleet managers can make Host Site Profile: Dallas Area

35th St. informed decisions when pur- Rapid Transit Alternative

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Transit BusesColucci Pkwy. C I I T R The participating host site for E D E M ST A AT ES OF

Produced for the U.S. Department of Energy (DOE) by the National Renewable DART’s LNG Bus Fleet • AFVs can be used more widely this study was DART, a public Energy Laboratory (NREL), a U.S. DOE national laboratory Start-Up Report Alt Blvd. and successfully to reduce U.S. transit agency based in Dallas, consumption of imported petro- Texas. DART operates more

35th St. leum and to benefit users and than 1,000 buses, railcars, and the environment. vans. Its buses cover more than Craig Ave. Colucci Pkwy. 130 local and express routes in DART’s LNG Bus Fleet Final Results a 700 square mile service Alt Blvd. The Transit Bus Evaluation Project area that includes Dallas and 12 suburban cities. The overall objective of the ongoing DOE/NREL Alternative DART estimates that it serves Fuel Transit Bus Evaluation Project more than 200,000 passengers is to compare heavy-duty buses daily, including rail (see using an alternative fuel with those Figure 1). DART is a leader in using conventional diesel fuel. business development and Specifically, the program seeks to environmental-minded policy, provide comprehensive, unbiased and won the 1997 Transit Agency evaluations of the newest genera- of the Year award from the tion of alternative fuel engine and American Public Transportation vehicle technologies. Association.

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DART’s LNG Buses buses to 380 miles. (The LNG DART’s fleet now includes 139 LNG buses were originally designed buses. The first of the 110 LNG with a three-tank system.) The buses ordered from NovaBUS 49 LNG buses already in Dallas (Roswell, New Mexico) were were modified at DART and delivered to DART in early 1998, NovaBus installed the fourth and began operating in November LNG tank in the 90 LNG buses 1998. Before any buses were delivered after April 1999. Figure 2 delivered, DART decided to shows an LNG bus at DART. increase the LNG bus order from Figure 3 shows one of the diesel 40 to 90 during the second year buses evaluated. of the contract and from 20 to 40 during the third year. In part because of operating range, fuel economy, and Because of lower than expected other engine-related issues, the range and fuel economy, DART DART contract with NovaBUS requested that NovaBUS add a was changed in July 1999 so fourth LNG tank on each bus to the last 60 LNG buses (of the increase the range of the LNG 200 ordered) would be diesel. Courtesy of DART/PIX 09175

Figure 1. DART bus and rail operations in Dallas, Texas 3 Alternative Fuel Final Results Transit Buses

Thus, 140 LNG buses were the addition of the fourth LNG planned in the final order. DART tank on each bus, and several needed more time to resolve modifications to the fuel gauges problems before adding more onboard the buses and to LNG LNG buses to the fleet. DART station operating procedures, the has had great success with the range problem was resolved by program infrastructure, but the September 1999. mobile side of the operations was disappointing in the beginning. As shown in Table 1, the 10 alternative fuel buses originally DART never accepted the first planned for evaluation in this LNG bus in the order (the pilot study were model year 1998 bus) because it needed design NovaBUS RTS-style buses changes. The LNG fleet at DART equipped with Cummins thus stood at 139 buses. With L10-280G engines. The 5 diesel buses used for comparison were also model year 1998 NovaBUS RTS-style buses, but they used Cummins M11-280 engines. The comparison of engines was deemed acceptable based on the similar maximum torque and horsepower of these models and Courtesy of DART/PIX 09148 on previous discussions with Cummins. Drivers reported no driving differences between the DART fleet NovaBUS LNG and the diesel buses.

The diesel buses in the evalua- tion started operating in May 1998. The LNG and diesel buses Figure 2. DART LNG bus on the road in Dallas, Texas were used to transport passen- gers along all routes served by DART’s Northwest facility.

To better understand fuel econ- omy and optimized operation of the LNG buses, 5 more LNG buses were added to the evalua- tion. These buses had design

Courtesy of DART/PIX 09149 enhancements to improve operating range and were placed into service in June 1999. (Throughout this report, the original 10 LNG buses will be referred to as the “original LNG buses;” the additional 5 buses will be referred to as the “new LNG buses.”) Figure 3. One of DART’s diesel buses

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Table 1. Vehicle Descriptions for DART Evaluation Buses

Description Diesel Control LNG

Number of Buses 5 10 original, 5 new

Chassis Manufacturer/Model NovaBUS, 40 foot NovaBUS, 40 foot

Chassis Model Year 1998 1998, 1999

Engine Manufacturer/ Cummins M11-280, 1998 Cummins L10-280G, 1998 Model, Year

Engine Ratings 280 hp @ 2000 rpm 280 hp @ 2100 rpm Max. Horsepower 900 lb-ft @ 1200 rpm 900 lb-ft @ 1300 rpm Max. Torque

Fuel System 125 gallons 4 LNG MVE, Inc. tanks, Storage Capacity 221 LNG gallons (132 diesel equivalent gallons)

Transmission ZF 5HP590 ZF 5HP590 Manufacturer/Model

Catalytic Converter Used (Y/N) Yes Yes

Curb Weight (lbs) 28,740 30,920

Gross Vehicle Weight (GVW) 39,500 39,500

Unless otherwise noted, all data for South Oak Cliff was completed in LNG buses in this report are from 1999 and started operating in the original set of 10 LNG buses. early 2000. Overall, DART in- vested approximately $16 million The LNG buses cost about between 1995 and 2000 for LNG $40,000 more than the diesel buses and facilities. buses DART ordered at the same time. The LNG buses cost DART has a long-standing com- approximately $330,000 each mitment to environmental (including the fourth LNG tank); improvement. In addition to the diesel buses cost about the 139 LNG buses, DART oper- $290,000 each. ates 2 CNG buses, 20 CNG trol- leys, 200 CNG paratransit vans, DART’s Involvement in Air and 148 CNG automobiles and Quality Improvement trucks. Overall, 41% of DART’s DART’s LNG program planning motor fuel fleet is powered by for fueling and bus ordering natural gas. began in 1995. Two LNG fueling stations were planned, one at Project Design and Northwest and one at South Oak Data Collection Cliff. The LNG fueling station at Northwest was completed in Data were gathered from DART’s 1998 (with modifications in fuel and maintenance tracking 1999 to optimize automatic systems daily. The data parame- controls), and the station at ters included 5 Alternative Fuel Final Results Transit Buses

• Diesel fuel consumption by DART staff had access to all data vehicle and fill being collected from their site and other data available from • LNG fuel consumption by the project. Summaries of the vehicle and fill data collected, evaluations, and • Mileage data from each vehicle analyses were distributed to des- • Dispatching logs ignated staff at DART for review and input. • Engine oil additions and oil/ filter changes The study design included the • Preventive maintenance action tracking of safety incidents affect- (PMA) work orders, parts lists, ing the vehicles or occurring at labor records, and related DART’s fueling station or in the documents maintenance facilities. However, no such incidents were reported • Records of unscheduled during the data collection period. maintenance (e.g., roadcalls [RCs]) • Records of repairs covered by manufacturer warranty

The data collection was designed to cause as little disruption for DART as possible. Data were sent from the transit site to an NREL contractor for analysis. DART generally sent copies (electronic and/or paper) of data that had already been collected as part of normal business operations.

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DART’s Facilities and Bulk Fuel Storage

DART operates nearly 1,000 buses and vans across 700 square miles in the Dallas, Texas, metro- politan area. These buses are operated from three bus facilities: • East Dallas Equipment Service Garage • Northwest Equipment Service Garage Courtesy of Kevin Chandler/PIX 07849 • South Oak Cliff Bus Operations Facility

Each facility operates about Figure 4a. DART buses parked under an open-air sunscreen at the Northwest 200 full-size transit buses. facility DART also has about 250 buses maintained and operated by a contractor.

The LNG buses are stored outside or under an open-air sunscreen to reduce the heat (Figure 4). For maintenance, the enclosed facilities at Northwest Courtesy of DART/PIX 09149 and South Oak Cliff were built with LNG in mind. The heating, ventilation, and air conditioning (HVAC) were rated with enough air changes to dissipate small nat- Figure 4b. DART buses parked outdoors at the Northwest facility ural gas leaks safely. The facilities are also equipped with infrared and methane/combustible gas suppliers and vendors included detectors and alarms. When the Chart Industries (formerly MVE, detectors measure methane at Inc.). The facility consists of two concentrations approaching the 30,000-gallon storage tanks, combustible range, visual and three pumps rated at 60 gallons audible alarms are activated and per minute (gpm) and 110 some of the overhead doors open pounds per square inch gauge, automatically. LNG buses are and three LNG dispensers parked outside if maintenance is (located alongside diesel fuel not completed during a work dispensers). shift. Figures 5 and 6 show the fueling In March 1998, DART commis- station from outside the North- sioned Lone Star Energy to west facility (no tanks showing) develop an LNG fueling station and inside with piping from the at the Northwest facility. Other tanks inside the canopy over to

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fueling. This cycle consists of recirculating the LNG in the piping from the fuel storage tanks to the dispensers (about 300 feet of piping) and the hose at the dispenser (about 65 feet per dispenser).

The cooldown cycle can take

Courtesy of Kevin Chandler/PIX 07177 12–30 minutes. The operation of the LNG fueling station is con- Figure 5. LNG fueling station at Northwest as seen from the street trolled from a computer at the shift manager’s station in the maintenance shop. The LNG buses are cleaned and fueled at the same islands as the diesel buses (three lanes and three sets of dispensers).

The fueling process at DART begins when the bus enters the fueling island. Each bus is Courtesy of Kevin Chandler/PIX 07850 equipped with an electronic hubodometer that communicates directly with the Fleetwatch® Figure 6. Northwest fueling station, showing canopy where fuel lines run from tracking system at the fueling tank to fueling lanes island. The Fleetwatch® system electronically records the type and amount of fuel, engine oil, and other fluids added to the bus. The data are periodically uploaded to the DART network computer system. Once fueling has begun at the Northwest station, LNG can be pumped at 50 gpm onboard the buses

Courtesy of Kevin Chandler/PIX 09197 (see Figure 8).

A sister LNG fueling station at DART’s South Oak Cliff facility was also installed by Lone Star Figure 7. DART fueling station receiving bulk LNG from supply Energy Company. It has two 20,000-gallon tanks, three pumps, and three dispensers. The station was constructed after the dispensers in the fueling the Northwest station, and the lanes. The Northwest LNG fueling design was modified to incorpo- facility was designed to service a rate lessons learned. maximum of 210 LNG buses nightly. Figure 7 shows the The cost for the two LNG stations and the maintenance facility Courtesy of DART/PIX 09179 station receiving bulk fuel from a Lone Star Energy tanker truck. modifications at Northwest and South Oak Cliff was about $7.5 Figure 8. LNG fueling hoses The station has a cooldown million for design, construction, connected to DART bus cycle that is required before LNG and start-up.

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Project Start-Up at DART

The first LNG bus was delivered to DART in January 1998, and What Is a Diesel Equivalent Gallon? began limited operations in the Dallas region. The LNG program Because LNG contains less energy per gallon than diesel fuel, compar- officially started in November ing simple miles per gallons of LNG and diesel trucks would not accu- 1998, when the first LNG buses rately compare their true fuel efficiencies. Diesel equivalent gallons began in revenue service. Early are commonly used to solve this problem. A diesel equivalent gallon in the deployment of the LNG is the quantity of LNG (or any other fuel) that contains the same buses, however, DART experi- energy as a gallon of diesel fuel. Because 1.67 gallons of LNG contain enced problems with operating the same energy as 1 gallon of diesel fuel, 1.67 gallons of LNG are range, fuel mileage, fuel filling, 1 diesel equivalent gallon. and reliability. These problems were partly related to the large size of DART’s LNG fleet and the capacity of the LNG industry to respond quickly to problems in has the the field. In addition to engine- 1 gallon 1.67 gallons same and fuel-related issues, DART of diesel of LNG energy as resolved problems with methane sensors, fire suppression systems, electronics, and multiplexing systems. (Some of the same problems also occurred with the diesel fleet.)

By spring 2000, DART had issues with spark plugs and resolved nearly all the problems wires, cylinder head design, the with the LNG buses by applying turbo actuator, coils, valves, and the lessons learned from start- the wastegate. Design work con- up and by cooperating with tinues to optimize the power manufacturers and component train and increase fuel economy suppliers. The LNG buses on the LNG buses. have been operating with no restrictions on all routes at the Range and Fuel Gauge Issues Northwest facility, except for a few of the longest routes. DART dispatches most buses on two runs during a standard operating day, with no midday LNG Engine Issues refueling. When the LNG buses Cummins resolved several prob- first began to operate, the range lems with early failure of engine was significantly lower than the components (e.g., turbocharger, required 400 miles. The expected spark plugs, and wastegate.) fuel economy for the LNG buses Some engine problems with the was approximately 2.2 mpg. In DART LNG buses persisted service for DART, the LNG buses through the end of the study had a fuel economy of approxi- period. Cummins is addressing mately 1.6 mpg, which is in line

9 Alternative Fuel Final Results Transit Buses

with the industry average for LNG tank had higher pressure LNG buses operating in a (higher resistance to having LNG “rough transit” duty cycle (i.e., flow in) or was “hotter” than the nearly 50% idle time and very other tanks. This would cause the low average speed). other tanks to fill first and the fuel nozzle would occasionally The LNG buses were originally shut down automatically because designed with a three-tank of back pressure before filling the system that provided 154 usable higher pressure tank. LNG gallons. At 1.62 mpg, this provided a range of only To ensure all tanks were filled 250 miles in service (277 miles with fuel, a level indicator and in track tests). In July 1999, DART pressure indicator for each tank asked NovaBUS to add a fourth were installed at the fuel fill loca- LNG tank, which made the total tion on each bus (Figure 9). The usable LNG capacity 221 gallons. fueler can thus easily see whether This gave the LNG buses a range a tank is not filled completely of 358 miles in service (380 miles and can restart the fueling in track tests), which has been process. As a last resort, the fuel- acceptable for DART’s service. er can start the vent filling proce- dure by manually opening the The desire to maximize range vent valve for each tank that is required ensuring a full fill not full. Because each vent valve of LNG onboard the buses. is on the end of a tank, the fueler Originally, the fuel level indicator may have to crawl under the bus could show nearly full when one to open and close the valve. This fuel tank was nearly empty. This adds 10 to 15 minutes to the situation occurred when one fueling process.

Other Fueling Issues The nozzle used for transferring LNG into the bus sometimes leaked and needed to be rebuilt. Leaking causes ice to form on the nozzle, which makes connecting

Courtesy of DART/PIX 09180 and disconnecting the nozzle dif- ficult, and damages the seal on the nozzle. The nozzle was redesigned by the vendor, J.C. Carter, and by the end of data collection seemed to work better.

Another fueling issue has been the need for a breakaway fueling hose to prevent damage and fuel loss when the bus is driven away from the fuel station while the LNG hose is still connected. This occurred five times at the Northwest station, causing signifi- Figure 9. Fuel level and pressure indicators on LNG buses at DART cant damage to the dispenser. One possible solution is to add a breakaway fitting (standard 10 Final Results Alternative Fuel Transit Buses

equipment in CNG, diesel, and Lessons Learned at Start-Up* gasoline fueling systems) to the hose. Another option is to add • Transit agency employees should learn all they can about the an electrical circuit to disable alternative fuel being introduced, the vehicles involved in the the starter on the bus when the project, and potential problems with alternative fuels in field fueling door is open. operations. Agencies should do extensive advance planning, including planning for unexpected contingencies, and exercise patience through the start-up process.

• Critical vehicle systems should undergo engineering design validation and/or performance tests before vehicles are put into service.

• Transit agencies need to be committed to success and to invest the personal energy, infrastructure, and financial resources to make alternative fuel programs work.

• The LNG industry needs to improve its own technology support infrastructure, and be able to respond to the needs of large fleets of LNG vehicles. The support required for 100-plus LNG vehicles in revenue service is far greater than the support Alternative

required for a few or a dozen in a demonstration project. ME RT NT PA O E F

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S A T A IC • All critical systems, including engines, onboard and T E ER S M U.S. DepartmProduced for theO F A by the National Renew ent of Energy (DOE) Transit Buses Energy Laboratory (NREL), stationary fuel equipment, chassis, and day-to-day a U.S. DOE national laboratory operations, need to be integrated through the use of able strong communication and accurate information within the transit agency.

35th St.

Colucci Pkwy. *A report that focuses on DART’s start-up experi- Craig Ave. ence is available from the National Alternative Fuels Hotline (1-800-423-1363) or on the World DART’s LNG Bus Fleet Wide Web (http://www.afdc.doe.gov). Alt Blvd.

Final Results

11 Alternative Fuel Final Results Transit Buses

Evaluation Results

By the end of the evaluation however, showed the lowest period, both the LNG and the operating cost per mile, at diesel fleets were doing the $0.713—about 8% lower than work DART expected. The major the diesel buses. difference in operations was that early on, the period of restricted operation for the LNG buses Bus Use in Transit Service meant that the diesel buses were The buses and data collection operated for more miles than the periods used in this study are LNG buses. shown in Table 2.

The LNG buses emitted less The fuel and maintenance data nitrogen oxides and particulate for all vehicles were collected matter than the diesel buses. By between the start of service and most other measures of opera- January 2000. The analyses and tion, the diesel buses performed evaluation in this report focus on better than the LNG buses. The only the data periods shown in LNG buses had a lower energy Table 2. The maintenance data equivalent fuel economy, higher periods were chosen to match fuel costs per mile driven, and similar vehicle lifetimes for the higher engine and fuel system diesel and LNG buses. The maintenance costs per mile vehicle lifetimes began after the driven than the diesel buses. first PMA and then run for about 1 year of service (except for the Overall, the operating cost com- new LNG buses, which ran for parison was mixed. The operat- 7 months). This was done to ing costs for the original LNG represent the same operational buses averaged about 3% higher time frame for each fleet than for the diesel buses. The being evaluated. LNG buses averaged $0.799 per mile. The diesel buses averaged The diesel and LNG buses at $0.773 per mile, giving the diesel DART are used 6 days a week, buses an advantage of $0.026 12 or more hours a day. Some per mile. The new LNG buses, buses also run on Sunday. Early

Table 2. Evaluation Vehicles and Data Evaluation Periods

Bus Fleet Bus Numbers Start of Fuel Data Maintenance Service Period Data Period

Diesel 4220–4224 May 1998 Feb 99–Jan 00 Jun 98–Jun 99

Original LNG 4320–4329 Nov 1998 Feb 99–Jan 00 Jan 99–Jan 00

New LNG 4502, 4513, 4535, 4536, 4539 Jun 1999 Jun 99–Jan 00 Jun 99–Jan 00

12 Final Results Alternative Fuel Transit Buses

during the start of operation Figure 10. Monthly average mileage per bus of the LNG buses, the reduced range caused the LNG buses to 6000 be used on only a few routes x 5000 during the week and not much x x x x x x on the weekends. Once the 4000 range problems were resolved with the fourth LNG tank and 3000 optimization of the LNG system, all the LNG buses could be used 2000 in the same way the diesel buses 1000 were used. Once the range restriction was lifted, all buses 0 were randomly dispatched on Feb-99 Mar-99 Apr-99 May-99 Jun-99 Jul-99 Aug-99 Sep-99 Oct-99 Nov-99 Dec-99 Jan-00 one or two routes. Only a few of Diesel LNG x New LNG the longest routes were restricted to diesel buses.

Average Speed Figure 11. Average monthly miles driven per bus Because the LNG buses had shorter range in the beginning, 4320 they were restricted from some 4321 of the routes. Therefore, their 4322 average speed was slightly higher 4323 (14.4 mph), compared to the average speed for the diesel 4324 buses (13.7 mph). Once the 4325 fourth LNG tank was installed Original LNG 4326 and optimized, the LNG buses 4327 were operated on all routes from 4328 the Northwest facility, except as 4329 mentioned. With the increased AVG range, the LNG and diesel bues had the same average speed. 4502

4513

Monthly Miles Driven 4535

4536

The LNG buses traveled as much New LNG as 34% fewer miles each month 4539 than the diesel buses during the AVG period of restricted operation. Figure 10 shows the monthly 4220 average mileage per bus for 4221 each fleet during the evaluation 4222 period (February 1999 through Diesel 4223 January 2000). Figure 11 shows the monthly average miles per 4224 bus. The diesel buses averaged AVG 4,321 monthly miles per bus 0 1000 2000 3000 4000 5000 and the original LNG buses Average monthly miles driven averaged 3,232 monthly miles Original LNG New LNG Diesel

13 Alternative Fuel Final Results Transit Buses

per bus, 25% lower during the Figure 12. Fuel economy evaluation period. The new LNG 4320 buses had the fourth LNG tank and full range since starting oper- 4321 ation in June 1999; hence, their 4322 average monthly miles per bus 4323 are in line with those of the

4324 diesel buses at 4,486 miles. The original LNG buses had a lower 4325 range than the diesel buses and Original LNG 4326 saw lower vehicle usage until 4327 September 1999 when the fourth LNG tank was installed. After Sep- 4328 tember 1999, the original LNG 4329 bus monthly mileage quickly AVG increased to the level of the diesel buses. 4502

4513 Fuel Economy, Maintenance,

4535 and Costs

4536 The LNG buses used more fuel New LNG per mile, so even though the 4539 LNG fuel cost was lower (on an AVG energy equivalent basis) than the comparable diesel fuel, fuel cost 4220 for DART was 32% more per mile 4221 for the LNG buses than for the

4222 diesel buses in the evaluation.

Diesel 4223 Fuel Economy 4224 Figure 12 shows the fuel AVG economy for the diesel, original 0 1 2 3 4 LNG, and new LNG buses. A Miles per gallon diesel equivalent gallon is the Miles per LNG gallon Diesel equivalent gallons were calculated based on quantity of LNG that contains a standard LNG gallon and divided by 1.67 (the Miles per diesel conversion factor for pure methane). The LNG used the same energy as 1 gallon of equivalent gallon during the evaluation was confirmed by DART’s fuel supplier to be essentially pure methane. diesel fuel. Diesel equivalent See sidebar page 9. Miles per diesel gallon gallons have been calculated based on a standard LNG gallon divided by 1.67, the conversion factor for pure methane. LNG at this site is essentially all methane (at least 98%, as required by contract), according to the fuel supplier, Lone Star Energy.

On average, the LNG bus fuel economy was 28% lower than the diesel bus fuel economy on a diesel equivalent gallon basis. 14 Final Results Alternative Fuel Transit Buses

Based on past experience with evaluation was $0.49 per LNG natural gas vehicles in heavy- gallon ($0.82 per diesel equiva- duty transit operation, the fuel lent gallon). economy difference is within the expected range of 15% to 30% Fuel Cost per Mile lower. The newer LNG buses with four LNG tanks had the Fuel consumption cost for the same average fuel economy as LNG buses was 32% higher the evaluation LNG buses. than for the diesel buses—LNG was $0.314 per mile and diesel Fuel economy measurements was $0.238 per mile. The fuel made at DART as part of the costs, coupled with the difference emissions testing on a chassis in energy equivalent fuel econ- dynamometer (described in detail omies, make up the fuel cost per in Appendix H of DART’s LNG mile. Fuel costs in the future for Bus Fleet Final Data Report, diesel and LNG could be different June 2000) show average LNG than the average fuel costs used bus fuel economy of 14% lower in this evaluation, depending on than the average diesel bus fuel changing fuel prices and changes economy on an energy equivalent in LNG vehicle fuel efficiency. basis over the Central Business District (CBD) driving cycle. This Engine Oil Consumption is substantially better than the and Cost 28% difference seen in actual operation. The DART LNG buses consumed 2.03 quarts of engine oil per The driving cycle for the buses 1,000 miles; the diesel buses has been different in service consumed 18% less (1.72 quarts than that tested by West Virginia per 1,000 miles). University (WVU) for emissions. Also, air conditioning was not Engine oil cost for the LNG running during the WVU testing engines was 31% higher per and there was little idle time quart than for the diesel during the emissions testing. In engines—$0.85 per quart for service, the diesel and LNG buses the LNG engines and $0.65 per typically spend 50% or more of quart for the diesel engines. the time idling with their air con- The higher cost oil for the LNG ditioning running. The natural engines is due to the low ash gas engines are spark-ignited and content specified by Cummins have higher fuel consumption at and the low volume purchase idle/low speed than the diesel of this oil by DART. (compression-ignition) engines. The oil cost per 1,000 miles for the diesel engines was $1; for the Fuel Cost per Gallon LNG engines it was $2. However, Diesel fuel costs rose significantly per-mile engine oil consumption during 1999, from $0.70 (February costs were very low compared to 1999) to $1.09 per gallon in fuel and maintenance costs. January 2000. The average diesel fuel cost used for the evaluation was $0.90 per gallon. The average cost for LNG fuel used for the 15 Alternative Fuel Final Results Transit Buses

Factors Affecting Maintenance Phasing the arrival of the new Costs buses also affected maintenance cost values. The diesel buses Maintenance costs for the were put into service 6 months DART evaluation were affected before the LNG buses. Therefore, by several unusual factors, most the troubleshooting and adjust- notably that the NovaBUS vehi- ments for the diesel buses cles were the first new buses occurred earlier on the “learning purchased by DART in more curve” for the DART staff. Issues than 10 years, and the first DART that were resolved with NovaBUS ever ordered from that manufac- and component suppliers during turer. Thus, the maintenance the first months of diesel bus staff had to adapt to a number operation resulted in lower of new technologies in the maintenance costs for the LNG diesel and LNG buses. New buses, because the changes had systems such as multiplexing of already been put in place, or controls onboard the bus because the time required to (instead of using hard wiring), make adjustments was reduced. computer-controlled engine and Similarly, the cost for trouble- transmission technologies (both shooting the 5 new LNG new to DART), antilock brake buses was lower than for the systems, and a new axle model original 10. were some of the systems DART engineers and maintenance staff had to learn and troubleshoot in Maintenance Costs by Vehicle a short time (see Figure 13). System Added to these technologies and Figure 14 shows the relative procedures were the LNG fuel share of the major systems con- systems, which were new to tributing to maintenance costs. DART’s transit bus operation. The portion of the maintenance costs for engine- and fuel-related systems was 8% higher for the LNG buses than for the diesel buses.

The top four categories ranked by cost are the same for the diesel, original LNG, and new LNG buses: Courtesy of DART/PIX 09176 1.Cab, body, and accessories (includes body repairs, repairs following accidents, glass, painting, cab and sheet metal repairs, seats, accessory repairs (such as radios), farebox, and hubodometer) 2.Engine- and fuel-related (includes exhaust, fuel, engine, non-lighting electrical, air intake, and cooling repairs) Figure 13. DART maintenance staff inspecting LNG fuel system

16 Final Results Alternative Fuel Transit Buses

3.PMA inspection (includes only higher for the original LNG Figure 14. Share of maintenance costs labor for inspections during buses and 2.4 times higher across major systems preventive maintenance) for the new LNG buses). Most LNG bus maintenance for the 4.Brakes All Other Maintenance fuel system was for labor to 21% Cab, Body, Accessories 38% The diesel bus maintenance costs troubleshoot problems such as were higher than expected for low power and fuel leaks. systems unrelated to the engine- • Engine system – Costs were Brakes and fuel-related systems. Only about 40% higher for the origi- 11% the engine- and fuel-related nal LNG buses and 3% lower systems would be expected to for the new LNG buses. PMA show differences between the 13% • Non-lighting electrical sys- LNG and diesel buses. In this Engine, Fuel tems – Costs were 39% higher 17% case, several systems unrelated for the original LNG buses and Diesel to the drivetrain required 56% higher for the new LNG significant maintenance for the buses. The parts and labor diesel buses. In the following costs were higher. Most parts All Other discussion, only the per-mile Maintenance costs for the original LNG 19% results from the similar vehicle Cab, Body, buses were due to spark plugs Accessories lifetimes are covered. 35% and wires changed as part of preventive maintenance. Brief summaries of the differ- Brakes 7% ences seen between the diesel • Air intake system – The costs and LNG fleets, and some of their were low and nearly the same causes, are as follows: for the diesel and the original PMA 14% • Cab, body, and accessories sys- LNG buses. For the new LNG buses, the cost was about half Engine, Fuel tems – Diesel bus maintenance 25% costs were about 17% higher that of the diesel buses. Original LNG because of problems with • Cooling system – The costs accessories such as surveillance were nearly the same for the equipment. diesel and the original LNG All Other buses. For the new LNG buses, Maintenance • Engine- and fuel-related sys- 11% Cab, Body, tems – The original LNG buses the cost was about half that of Accessories Brakes 40% had maintenance costs 33% the diesel buses. 8% higher than the diesel buses; • PMA inspections – As expected, the new LNG buses 10%. The costs were essentially the same PMA new LNG buses had a lower for the study fleets. There 16% maintenance cost difference should be no extra costs for than the original LNG buses inspections on any of the study because of lower labor costs for fleets, because the vehicles Engine, Fuel 25% troubleshooting. were in approximately the • Exhaust system – The mainte- same service. New LNG nance costs were 59% lower for • Brake system – Both study the original LNG buses and fleets of LNG buses had about 80% lower for the new LNG the same costs for brake buses than for the diesel buses. system maintenance. The • Fuel system – The LNG mainte- diesel buses required more nance costs were much higher labor to troubleshoot the than the diesel buses (3 times antilock brake systems.

17 Alternative Fuel Final Results Transit Buses

• Lighting system – The mainte- • Axle, wheel, and drive shaft nance costs were about 34% systems – Maintenance costs lower for the original LNG for the study buses were low. buses and 70% lower for the new LNG buses than for the Roadcalls diesel buses. An RC is defined in this report • Tire systems – All tire costs as an on-road failure of an in- were covered under a lease service transit bus that requires a arrangement, with a consistent replacement bus to be dispatched cost of $0.0051 per mile for to complete the route. If the failed tire replacements. bus is fixed on the road and put • Transmission – The mainte- back into service immediately, this nance costs were about 73% is not considered an RC. higher for the original LNG buses and 55% lower for the Figure 15 shows average miles new LNG buses than for the between RCs for the diesel and diesel buses. The original LNG buses for all data. This LNG buses had higher costs chart shows that the trend for because of higher parts costs each study fleet is upward and and occasional unscheduled indicates the progress DART has maintenance. made toward troubleshooting and resolving start-up problems. • HVAC systems – The original LNG buses had maintenance The low miles between RCs for costs 12% lower than the the diesel buses were caused by diesel buses; the new LNG systems other than the engine- buses 76% lower. The diesel and fuel-related systems, and the and original LNG buses LNG buses have had many more required significant labor hours engine- and fuel-related issues. For for troubleshooting problems engine- and fuel-related systems, with the air conditioning both sets of LNG buses had miles motors and problems that were between RC results that were mostly covered under warranty. 50% lower than the diesel buses. • Air system – Most repairs for the air system are assigned to Warranty Costs the brakes, door, and suspen- On a cost per bus basis across all sion systems. These were low data collected, the diesel buses overall but slightly higher for had the highest costs for warranty the diesel buses. repairs ($17,101.54). The per-bus • Frame, steering, and suspen- costs were lower for the original sion systems – The diesel bus LNG buses, at $10,660.65. The maintenance costs were nearly new LNG buses had the lowest double those for the LNG per-bus costs, at $8,674.57. buses. These higher costs were caused mostly by bumper This trend is consistent with module replacements due to DART and NovaBUS working minor accidents and labor for through the maintenance prob- problems with radius rod lems of the buses as they arrived. replacements covered by In this analysis the diesel buses the warranty. were put into service 6 months

18 Final Results Alternative Fuel Transit Buses

before the first LNG buses and a Figure 15. Average miles between RCs for diesel, original LNG, year before the new LNG buses. and new LNG buses (does not include out-of-fuel RCs) The highest warranty cost 6000 systems for each fleet were as follows: 5000 • Diesel – body, cab, accessories; 4000 x HVAC; non-lighting electrical; x x x x axles, wheels, drive shaft; x x x x x x x x and frame, steering, and 3000 x suspension • Original LNG – engine/fuel- 2000 x related; body, cab, accessories; non-lighting electrical; HVAC; 1000 fuel; and axles, wheels, and drive shaft 0 May-98 July-98 Sep-98 Nov-98 Jan-99 Mar-99 May-99 July-99 Sep-99 Nov-99 Jan-00 • New LNG – body, cab, acces- sories; non-lighting electrical; DSL Avgx LNG Avg New LNG Avg exhaust; and engine/fuel related

Overall Maintenance Costs The following analysis covers This difference was caused by total maintenance costs for maintenance of accessory similar vehicle lifetime periods systems. Engine- and fuel-related with no warranty work included. systems maintenance costs Similar vehicle lifetimes were were significantly higher for chosen to represent the period the original LNG buses, as beginning after the first PMA and discussed earlier. running for about 1 year. Focus- ing on only the similar vehicle Total maintenance costs per mile lifetime results, the vehicle usage for the new LNG buses were has been 17% higher for the much lower than for the diesel diesel buses. buses. These costs were lower because in the accessory systems Figure 16 shows the total mainte- many of the problems with the nance costs per bus across the diesel buses were resolved for original LNG, new LNG, and the LNG buses. Also, the preven- diesel fleets evaluated. The tive maintenance costs were original LNG buses showed lower because the data evalua- significantly lower parts costs tion period was shorter than the per bus than the diesel buses. full year used for the diesel and The labor hours were also lower original LNG bus evaluation. for the original LNG buses. (Labor costs were calculated Overall Operating Costs using a constant average rate of $50 per hour.) Figure 17 provides a summary of operating costs for the diesel, The original LNG buses had a original LNG, and new LNG total maintenance cost per mile study groups of buses. These 9% lower than the diesel buses. results are only for the similar

19 Alternative Fuel Final Results Transit Buses

g p Figure 16. Total maintenance costs per bus In Calculating the Overall Operating Costs: 80,000 10,000 500 1.0 • Vehicle and fueling station capi-

70,000 tal costs and driver labor were not included 8,000 400 0.8 60,000 • Actual fuel costs during the study were used: 50,000 6,000 300 0.6 • Diesel: $0.90 per gallon 40,000 • LNG: $0.85 per diesel energy 4,000 200 0.4 equivalent gallon 30,000 • Maintenance costs did not 20,000 include warranty repairs paid 2,000 100 0.2 for by the manufacturers 10,000 • Maintenance labor cost was

0 0 0 0 assumed to be $50 per hour Avg Miles Avg Parts Cost Avg Labor Hours Total Maintenance per Bus per Bus in $ per Bus Cost per Mile in $ Emissions Testing Results Original LNG New LNG Diesel Emissions tests on the diesel and original LNG buses were con- ducted by the WVU Department of vehicle lifetime data periods. Mechanical and Aerospace Engi- Total operating costs include fuel neering using one of its trans- and maintenance costs, and portable heavy-duty chassis dyna- exclude driver labor. Engine oil mometer emissions laboratories. costs were low (maximum $0.002 (These laboratories were devel- per mile). oped under DOE sponsorship.) WVU used the CBD speed-versus- Overall, the three fleets analyzed time cycle to evaluate each bus. had very similar operating costs, ranging from a low of $0.713 per Tests were conducted in February mile for the new LNG buses to and March 1999. Results are $0.773 for the diesel buses, and to shown in Figure 18. The LNG a high of $0.799 for the original buses had less of all four regu- LNG buses. lated emissions than the diesel buses. The LNG buses were much This means that the original LNG lower in carbon monoxide and buses had operating costs 3% particulate matter emissions than higher than the diesel buses. The the diesel buses. Although the new LNG buses had operating nitrogen oxide emissions were costs 8% lower than the diesel quite variable, on average, the buses. The total maintenance LNG buses had 17% lower costs were higher for the diesel nitrogen oxide emissions than buses as explained earlier; how- the diesel buses. The LNG buses ever, for the engine- and fuel- also had significantly lower related systems, the original LNG non-methane hydrocarbons than buses had costs 33% higher, and the diesel buses (assumed to be the new LNG buses had costs non-methane). Both fleets were 10% higher than the diesel buses. equipped with oxidation catalysts. 20 Final Results Alternative Fuel Transit Buses

In general, the diesel buses had Figure 17. Overall operating costs per mile in $ relatively low emissions results because oxidation catalysts were used. However, the LNG bus emissions were still significantly Fuel Cost per Mile lower than those of the clean diesel buses.

The average miles per diesel Maintenance equivalent gallon obtained Cost per Mile during emissions testing for the LNG buses were much higher than the result obtained from Total Cost in-use fuel economy data. As per Mile discussed in the fuel economy section, however, the CBD cycle used in emissions testing differed 0 0.25 0.50 0.75 1.0 from the actual revenue service Cost per Mile in $ duty cycle for the diesel and LNG Original LNG New LNG Diesel buses. In addition, the CBD cycle does not take into account peri- ods of idling with auxiliary loads such as air conditioning.

Figure 18. Emissions testing results 30

NOx - Oxides of nitrogen PM - Particulate matter HC - Hydrocarbon NMHC - Non-methane hydrocarbon 20 CO - Carbon monoxide CO2 - Carbon dioxide MPEG - Miles per diesel equivalent gallon

10

a 0 NOx, g/mi PM x 10, g/mi HC/NHMC x 10, g/mi CO, g/mi CO2/100, g/mi MPEG a. PM values for LNG were below the detectable limit (<0.01g/mi)

Original LNG Diesel

21 Alternative Fuel Final Results Transit Buses

LNG Technology Progress in Transit

LNG transit bus technology was onboard the bus. Houston Metro evaluated in the original used the Detroit Diesel (DDC) DOE/NREL evaluation report 6V92TA PING (pilot injection nat- from 1996 (Alternative Fuel ural gas) dual-fuel (natural gas Transit Buses, Final Results from and diesel fuel together) engine the National Renewable Energy for LNG operations. This engine Laboratory Vehicle Evaluation is no longer available from DDC, Program). In this report, LNG and Houston Metro has phased transit buses were studied at most of them out. Tri-Met used Houston Metro (Houston, Texas) the Cummins L10-240G engine and Tri-Met (Portland, Oregon). for LNG operations. This engine One conclusion was that, because used open loop natural gas fuel the LNG technology evaluated at system technology, and is no these sites was considered early longer available from Cummins. development equipment, another LNG site evaluation was needed The LNG technology being to investigate operating costs and planned at DART was the newest reliability on more mature LNG available in the industry using fuel system technology that did the Cummins L10-280G engine not use a cryogenic pump and a fuel system from MVE, Inc.,

Table 3. Vehicle Descriptions for LNG Evaluation Buses

Description Houston Metro Tri-Met DART

Number of LNG Buses 10 10 10

Chassis Manufacturer/Model Mercedes, 40 foot Flxible, 40 foot Nova Bus, 40 foot

Chassis Model Year 1992 1993 1998, 1999

Engine Manufacturer/Model DDC 6V92TA PING Cummins L10-240G Cummins L10-280G

Engine Ratings Max. Horsepower 277 hp @ 2100 rpm 240 hp @ 2100 rpm 280 hp @ 2100 rpm Max. Torque 840 lb-ft @ 1200 rpm 750 lb-ft @ 1300 rpm 900 lb-ft @ 1300 rpm

Fuel System 70 gallons 174 gallons LNG 221 gallons LNG Storage Capacity 43 gallons diesel

Transmission Allison, HTB-748 Voith, D-863 ADR ZF 5HP590 Manufacturer/Model

Catalytic Converter Used (Y/N) No Yes Yes

Curb Weight (lbs) 30,560 30,030 31,000

Gross Vehicle Weight (GVW) 39,500 39,500 39,500

22 Final Results Alternative Fuel Transit Buses

without a cryogenic pump. Both Figure 19. Miles between roadcalls the engine and the fuel system had been used in several vehicle Entire Bus applications. DART also chose to Houston buy diesel buses that would

match the LNG technology buses Tri-Met almost identically, excluding the engine and the fuel system. This DART section investigates how the DART LNG results compare to the Engine- and Fuel-Related Systems Only earlier technology at Houston Metro and Tri-Met. Table 3 shows Houston a summary of vehicle descrip- tions for Houston Metro, Tri-Met, Tri-Met and DART LNG buses. DART Roadcalls 0 2000 40006000 8000 10000 12000 14000 16000 18000 20000 Figure 19 shows mileage between Diesel LNG RCs for Houston Metro, Tri-Met, and DART during the evaluation period. The first set of bars shows RCs for all systems Houston Metro LNG buses were (including the door, wheelchair 3.8 times (280%) higher than for lifts, and other features); the the diesel buses at Houston second set is for the engine- Metro. At Tri-Met, engine- and and fuel-related systems (engine, fuel-related maintenance costs fuel, non-lighting electrical, air for the LNG buses were 1.6 times intake, and cooling). In the early (60%) higher than for the diesel LNG fleets at Houston Metro and buses. At DART, the engine and Tri-Met, the diesel buses traveled fuel-related maintenance costs significantly further between RCs. At DART, the distance between RCs was essentially the same for the diesel and the LNG buses. Figure 20. Operational costs per mile ($) The engine- and fuel-related sys- $1.20 tems results show that the DART LNG buses ran a much longer $1.00 distance between RCs than the Houston Metro or Tri-Met LNG $0.80 buses. However, these systems resulted in more RCs for LNG $0.60 than for diesel at all three sites.

$0.40 Maintenance Costs Figure 20 shows total operating $0.20 costs by vehicle group at DART, Tri-Met, and Houston Metro. For $0.00 DART Diesel DART LNG Tri-Met Diesel Tri-Met LNG Houston Diesel Houston LNG engine- and fuel-related systems

maintenance (the bottom portion Eng/Fuel Maint. Other Maint. Fuel & Oil of the stacked bars), costs for the

23 Alternative Fuel Final Results Transit Buses

were only 1.3 times (33%) gallon basis. The Houston Metro higher than for the diesel buses. LNG buses had the best fuel (The maintenance data for all economy, but the dual-fuel three sites were calculated with LNG/diesel buses were not oper- a constant labor rate of $50 per ated in LNG mode often. The hour. For the 1996 report, $25 dual-fuel buses could operate on per hour was used.) The engine- diesel only, and were rarely used and fuel-related maintenance in the dual-fuel mode. There costs for LNG buses were signifi- were problems with the dual-fuel cantly lower at DART than at operation of the LNG buses at Houston Metro or Tri-Met. Houston. The Tri-Met LNG buses had a fuel economy 30% lower The overall maintenance costs at than the diesel buses at Tri-Met. Houston Metro and Tri-Met were This result is consistent with the significantly higher for the LNG DART LNG buses having a fuel buses than for the diesel control economy 28% lower than the buses. At DART, the LNG and diesel buses at DART. However, diesel bus maintenance costs this is a similar fuel economy were comparable. difference for an LNG bus with a higher horsepower engine Fuel Economy (240 hp at Tri-Met and 280 hp at DART). Figure 21 shows fuel economy results for Houston Metro, Tri-Met, and DART for the LNG Emissions Testing Results and diesel buses at each site. For emissions testing results from Houston Metro LNG buses WVU’s mobile chassis dynamome- showed a 13% lower fuel ter, results from early natural gas economy on a diesel equivalent engines were generally erratic because of the open loop fuel control design. This was true Figure 21. Fuel economy results in miles per diesel equivalent gallon for Houston Metro and Tri-Met LNG buses. For the spark-ignited $4.50 Cummins engine at Tri-Met, the $4.00 LNG buses showed extremely low particulate matter results $3.50 (0.02 to 0.03 g/mi compared to $3.00 the diesel buses that averaged 1.96 to 2.18 g/mi). Carbon $2.50 dioxide emissions were about

$2.00 the same for the LNG and diesel buses (2430 g/mi). However, $1.50 carbon monoxide and nitrogen

$1.00 oxide could be low for the LNG buses, but could also be very $0.50 high. On average, the carbon

$0.00 monoxide results for the LNG Houston Metro Tri-Met DART buses were about the same as the diesel buses (10 g/mi), but were

Diesel LNG as low as 0.01 g/mi and as high as 58.8 g/mi. On average, the older

24 Final Results Alternative Fuel Transit Buses technology nitrogen oxide results for the LNG buses were about 20% higher than the average for the diesel buses (41 to 45 g/mi for diesel buses), but were as low as 31 g/mi and as high as 67 g/mi. The wide swings in emissions results were attributed to the tune of the engine or improperly functioning fuel control on the LNG buses.

For the DART LNG and diesel buses on the CBD cycle, the emissions results were much more consistent and generally lower for the LNG buses. The LNG buses at DART had an average of 0.23 g/mi for carbon monoxide, 21.3 g/mi nitrogen oxide, and particulate matter that was lower than the detectable limit of WVU’s equipment, <0.01 g/mi. The diesel buses at DART were much cleaner than earlier diesel bus emissions: 4.44 g/mi for carbon monoxide, 25.5 g/mi nitrogen oxide, and 0.32 g/mi for particulate matter.

Summary Generally, the results of the DART LNG bus evaluation show that emissions, reliability, and maintenance costs have improved significantly from earlier LNG bus designs evaluated in the 1996 study. Overall bus reliability and maintenance costs were comparable with diesel. The reliability and maintenance costs for the engine- and fuel-related systems have improved compared with diesel technology, but are not yet at the same level.

25 Alternative Fuel Final Results Transit Buses

Summary and Conclusions

Based on the evaluation of the • Some engine problems DART LNG transit buses, we can continue to cause difficulties conclude several major points: for the DART LNG buses. Cummins is still working on • DART has had significant these problems even though problems, especially related the L10 engine has been dis- to range, with start-up of LNG continued as a commercial operations. The buses were product. The resolution of specified to have a 400-mile problems with the L10 is range and could achieve only applicable to the C8.3G, 277 miles. A fourth LNG tank Cummins’ current heavy-duty was added for onboard storage natural gas engine for the of LNG. This fourth tank pro- transit market. Cummins is vided enough fuel to achieve a addressing issues with spark range of 380 miles, which plugs and wires, cylinder head DART deemed acceptable. Sev- design, turbo actuator, coils, eral other problems with early and wastegate. failure of engine components (turbocharger, spark plugs, • Emissions testing results from exhaust valve, and wastegate), WVU showed that the diesel fuel system (leaks), the fueling engines at DART were very station nozzle, and other sys- clean. The LNG emissions were tems have nearly all been cleaner yet. This emissions test- resolved through a team effort ing at DART was a state-of-the- at DART and with the vendors. art comparison for transit with 1998 technology. • As of the end of the study period, the LNG buses were • Total operating costs for the being treated the same as the LNG buses were only 3% diesel buses in meeting the higher than the diesel buses. daily pullout requirements. However, the maintenance costs for the engine- and fuel-related • The drivers report that the systems were 33% higher for the LNG buses are well matched in LNG buses than for the diesel performance to diesel; drivers buses. The fuel costs were 32% have difficulty telling the buses higher for the LNG buses than apart. for the diesel buses. • The fuel economy has been • Miles between RCs for the LNG steady at 1.62 miles per LNG and diesel buses overall were gallon or 2.70 miles per diesel about the same. The LNG buses equivalent gallon. DART, ZF, had 50% fewer miles between and Cummins continue to RCs for the engine- and fuel- explore ways to increase fuel related systems compared to economy by 5% to 10%. the engine- and fuel-related system RCs on the diesel buses.

26 Final Results Alternative Fuel Transit Buses

• The problems with range and • In 1996, DOE/NREL published the size of the LNG fleet at an evaluation report on LNG DART challenged the LNG and transit bus technology that natural gas vehicle industries. included buses at Houston A consortium of industry part- Metro and Tri-Met. The technol- ners on an “LNG task force” ogy was considered early devel- overcame the problems. At the opment equipment, and the end of the study, all 139 LNG report concluded that another buses were making pullout LNG site evaluation was needed nearly every day. to investigate the operating costs and reliability on more • The two LNG fueling stations mature LNG fuel system tech- are working well for DART. nology. DART was chosen as the Some problems have been site because the technology experienced with fueling noz- then being planned there was zle leaks and driveaways with the newest in the industry. damage to the dispensing sys- tem. The nozzle has been • The results of the DART LNG redesigned and seems to be bus evaluation show that emis- managing leaks better. DART is sions, reliability, and mainte- still exploring breakaway fitting nance costs have generally and hose designs. The new improved from earlier LNG bus LNG station at South Oak Cliff designs. The overall reliability does not have the extensive and maintenance costs were length of piping (300 feet) comparable with diesel; these from the storage tanks to the same costs for the engine- and fueling island that Northwest fuel-related systems have has. This has resulted in a improved compared with diesel much higher available fueling technology, but are not yet at rate, as high as 70 gpm. the same level.

Future LNG Operations at DART

The South Oak Cliff facility will New procurements for buses at $16 million for buses and facilities. house and maintain nearly half DART have a provision for LNG The two LNG fueling stations have the current LNG fleet. Fifty LNG buses. DART continues to evalu- significant capacity left: 139 LNG buses were moved to South Oak ate the operation of its LNG fleet. buses of a maximum 350 LNG Cliff in May 2000, and the new buses that could be filled nightly, LNG fueling facility there is oper- DART continues to work on opti- or 40% of capacity. DART has the ational. Both the Northwest and mizing the LNG bus operations. opportunity to use more of the South Oak Cliff operations facili- capacity of its fuel stations and ties have room to increase their One issue for LNG operations continue to reduce emissions by LNG fleets. is that DART has invested using LNG.

27 Alternative Fuel Final Results Transit Buses

Contacts

DART BATTELLE CHART-APPLIED TECHNOLOGIES Michael Hubbell Kevin Chandler George Laux Vice President, Maintenance Project Manager Senior Account Representative 4209 Main Street 505 King Avenue P.O. Box 12066 Dallas, TX 75266-7258 Columbus, OH 43201 Spring, TX 77391 214/828-6780 614/424-5127 281/890-6228

DART LONE STAR ENERGY COMPANY WEST VIRGINIA UNIVERSITY (Now a part of Blue Fuels) Rocky Rogers Nigel Clark Assistant Vice President Stanley T. Taylor Department of Mechanical & Technical Services General Manager Aerospace Engineering 4209 Main Street 300 South St. Paul Street Morgantown, WV 26506-6106 Dallas, TX 75266-7258 Suite 750 EC 304/293-3111 ext. 2311 214/828-6721 Dallas, TX 75201 214/875-3854 DART CUMMINS SOUTHERN PLAINS, INC. Darryl Spencer Fleet Systems Engineer Jason Ruble P.O. Box 660163 Regional Sales Manager Dallas, TX 75266-7258 600 N. Watson Road 214/828-6804 P. O. Box 90027 Arlington, TX 76004-3027 NREL 817/640-6896 Paul Norton NOVABUS Senior Engineer 1617 Cole Boulevard Dan Moats Golden, CO 80401 Engineering Project Manager 303/275-4424 42 Earl Cummings Loop West P.O. Box 5670 (R.I.A.C.) Roswell, NM 88202-5670 505/347-7350

28 Final Results Alternative Fuel Transit Buses

References and Related Reports

Battelle, 2000, DART’s LNG Bus Fleet Final Data Report, National Renewable Energy Laboratory, Golden, CO.

Battelle, 2000, DART’s LNG Bus Fleet, Start-Up Experience, National Renewable Energy Laboratory, Golden, CO, NREL/BR-540-28124.

Chandler, K., Norton, P., Clark, N., 2000, Raley’s LNG Truck Fleet, Final Results, National Renewable Energy Laboratory, Golden, CO, NREL/BR-540- 27678.

Battelle, 1999, Waste Management’s LNG Truck Fleet, Start-Up Experience, National Renewable Energy Laboratory, Golden, CO, NREL/BR-540-26617.

Battelle, 1999, Raley’s LNG Truck Site, Final Data Report, Battelle, Columbus, OH.

Chandler, K., Norton, P., Clark, N., 1999, Update from the NREL Alternative Fuel Transit Bus Evaluation Program, American Public Transit Association, 1999 Bus Conference, Cleveland, OH.

Chandler, K., Norton, P., Clark, N., 1999, Interim Results from Alternative Fuel Truck Evaluation Project, SAE International, Warrendale, PA, SAE Pub. #1999- 01-1505.

Clark, N., Lyons, D., Rapp, L., Gautam, M., Wang, W., Norton, P., White, C., Chandler, K., 1998, Emissions from Trucks and Buses Powered by Cummins L-10 Natural Gas Engines, SAE International, Warrendale, PA, SAE Pub. #981393.

Battelle, 1998, Dual-Fuel Truck Fleet, Start Up Experience, National Renewable Energy Laboratory (NREL), Golden, CO, NREL/BR-540-25118.

Battelle, 1998, Using CNG Trucks in National Parks, National Renewable Energy Laboratory (NREL), Golden, CO, NREL/BR-540-24744.

Chandler, Norton, Clark, 1998, Alternative Fuel Truck Evaluation Project – Design and Preliminary Results, SAE International, Warrendale, PA, SAE Pub. #981392.

Norton, P., Vertin, K., Bailey, B., Clark, N., Lyons, D., Goguen, S., Eberhardt, J., 1998, Emissions from Trucks Using Fischer-Tropsch Diesel Fuel, SAE Interna- tional, Warrendale, PA, SAE Pub. #982426.

Clark, N., Gautam, M., Lyons, D., Bata, R., Wang, W., Norton, P., Chandler, K., 1997, Natural Gas and Diesel Transit Bus Emissions: Review and Recent Data, SAE International, Warrendale, PA, SAE Pub. #973203.

Battelle, 1997, Raley’s LNG Truck Fleet, Start-Up Experience, National Renewable Energy Laboratory, Golden, CO, NREL/BR-540-23402.

Battelle, 1996, Alternative Fuel Transit Buses, The Pierce Transit Success Story, National Renewable Energy Laboratory, Golden, CO, NREL/SP-425- 21606. 29 Alternative Fuel Final Results Transit Buses

Chandler, K., Malcosky, N., Motta, R., Norton, P., Kelly, K., Schumacher, L., Lyons, D., 1996, Alternative Fuel Transit Bus Evaluation Program Results, SAE International, Warrendale, PA, SAE Pub. #961082.

Motta, R., Norton, P., Kelly, K., Chandler, K., Schumacher, L., Clark, N., 1996, Alternative Fuel Transit Buses, Final Results from the National Renewable Energy Laboratory Vehicle Evaluation Program, National Renewable Energy Laboratory, Golden, CO, NREL/TP-425-20513.

Chandler, K., Malcosky, N., Motta, R., Kelly, K., Norton, P., Schumacher, L., 1996, Final Alternative Fuel Transit Bus Evaluation Results, Battelle, Columbus, OH.

Wang, W., Gautam, M., Sun, X., Bata, R., Clark, N., Palmer, G., Lyons, D., 1993, Emissions Comparisons of Twenty-Six Heavy-Duty Vehicles Operated on Con- ventional Alternative Fuels, SAE International, Warrendale, PA, SAE Pub. #932952.

Bata, R., Clark, N., Gautam, M., Howell, A., Long, T., Loth, J., Lyons, D., Palmer, M., Rapp, B., Smith, J., Wang, W., 1991, The First Transportable Heavy Duty Vehicle Emissions Testing Laboratory, SAE International, Warrendale, PA, SAE Pub. #912668.

30 Final Results Alternative Fuel Transit Buses

Appendix A Fleet Summary Statistics

31 Alternative Fuel Final Results Transit Buses

Dallas Area Rapid Transit (Dallas, TX) Fleet Summary Statistics

Fleet Operations and Economics Diesel LNG LNG Control 4300 4500 Number of Vehicles 5 10 5 Period Used for Fuel and Oil Op Analysis 2/99-1/00 2/99-1/00 6/9-1/00 Total Number of Months in Period 12 12 8 Fuel and Oil Analysis Base Fleet Mileage 218,672 369,563 171,358 Period Used for Maintenance Op Analysis 6/98 - 5/99 1/99 - 1/00 7/99 - 1/00 Total Number of Months in Period 12 12 6 Maintenance Analysis Base Fleet Mileage 243,606 402,618 143,429 Average Monthly Mileage per Vehicle 4,321 3,232 4,486 Fleet Fuel Usage in Diesel #2 Equiv. Gal. 57,849 136,743 63,415 Representative Fleet MPG 3.78 1.62 1.62 Representative Fleet MPG (energy equiv) 3.78 2.70 2.70 Ratio of MPG (AF/DC) 0.71 0.71 Average Fuel Cost as Reported (with tax) 0.90 0.51 0.51 per Gal D2 per Gal LNG per Gal LNG Average Fuel Cost per Energy Equivalent 0.90 0.85 0.85 Fuel Cost per Mile 0.238 0.314 0.314 Number of Make-Up Oil Quarts per Mile 0.002 0.002 0.001 Oil Cost per Quart 0.65 0.85 0.85 Oil Cost per Mile 0.001 0.002 0.001 Total Scheduled Repair Cost per Mile 0.114 0.115 0.102 Total Unscheduled Repair cost per Mile 0.420 0.368 0.296 Total Maintenance Cost per Mile 0.534 0.484 0.398 Total Operating Cost per Mile 0.773 0.799 0.713

Maintenance Costs

Diesel LNG LNG Control 4300 4500

Fleet Mileage 243,606 402,618 143,429 Total Parts Cost 33,807.74 54,219.93 17,228.68 Total Labor Hours 1925.6 2809.1 797.8 Average Labor Cost 96,280.00 140,454.50 39,887.50 (@ $50.00 per hour) Total Maintenance Cost 130,087.74 194,674.43 57,116.18 Total Maintenance Cost per Mile 0.534 0.484 0.398

32 Final Results Alternative Fuel Transit Buses

Breakdown of Maintenance Costs by Vehicle System Similar Vehicle Lifetimes

Diesel LNG LNG Control 4300 4500 Fleet Mileage 243,606 402,618 143,429

Total Engine/Fuel-Related Systems (ATA VMRS 30,31,32,33,41,42,43,44,45)

Parts Cost 6,471.72 12,121.26 5,330.47

Labor Hours 315.8 739.7 182.6

Average Labor Cost 15,791.50 36,985.00 9,127.50

Total Cost (for system) 22,263.22 49,106.26 14,457.97

Total Cost (for system) per Mile 0.0914 0.1220 0.1008

Exhaust System Repairs (ATA VMRS 43)

Parts Cost 102.44 120.38 35.87

Labor Hours 19.6 12.2 2.0

Average Labor Cost 981.00 608.50 100.00

Total Cost (for system) 1,083.44 728.88 135.87

Total Cost (for system) per Mile 0.0044 0.0018 0.0009

Fuel System Repairs (ATA NVMRS 44)

Parts Cost 87.16 623.43 601.01

Labor Hours 22.3 106.3 21.6

Average Labor Cost 1,112.50 5,312.50 1.077.50

Total Cost (for system) 1,199.66 5,935.93 1,678.51

Total Cost (for system) per Mile 0.0049 0.0147 0.0117

Power Plant (Engine) Repairs (ATA VMRS 45)

Parts Cost 3,375.43 4,062.19 1,406.39

Labor Hours 82.1 262.1 57.8

Average Labor Cost 4,103.50 13,107.00 2,887.50

Total Cost (for system) 7,472.93 17,169.19 4,293.89

Total Cost (for system) per Mile 0.0307 0.0426 0.0299

Electrical System Repairs (ATA VMRS 30-Electrical General, 31-Charging, 32-Cranking, 33-Ignition)

Parts Cost 1,082.18 5,325.12 2,801.24

Labor Hours 134.7 254.0 88.0

Average Labor Cost 6,733.00 12,701.00 4,400.00

Total Cost (for system) 7,815.18 18,026.12 7,201.24

Total Cost (for system) per Mile 0.0321 0.0448 0.0502

33 Alternative Fuel Final Results Transit Buses

Breakdown of Maintenance Costs by Vehicle System (continued)

Diesel LNG LNG Control 4300 4500 Air Intake System Repairs (ATA VMRS 41)

Parts Cost 1,325.24 1,667.41 354.74

Labor Hours 22.3 24.5 5.5

Average Labor Cost 1,112.50 1,222.50 275.00

Total Cost (for system) 2,437.74 2,889.91 629.74

Total Cost (for system) per Mile 0.0100 0.0072 0.0044

Cooling System Repairs (ATA VMRS 42)

Parts Cost 499.27 322.73 131.21

Labor Hours 35.0 80.7 7.8

Average Labor Cost 1,749.00 4,033.50 387.50

Total Cost (for system) 2,248.27 4,356.23 518.71

Total Cost (for system) per Mile 0.0092 0.0108 0.0036

Brake System Repairs (ATA VMRS 13)

Parts Cost 1,434.07 4,077.77 1,585.65

Labor Hours 218.3 200.2 54.5

Average Labor Cost 10,915.50 10,009.00 2,725.00

Total Cost (for system) 12,349.57 14,086.77 4,310.65

Total Cost (for system) per Mile 0.0507 0.0350 0.0301

Transmission Repairs (ATA VMRS 27)

Parts Cost 1,037.26 2,519.44 526.34

Labor Hours 50.0 81.0 1.5

Average Labor Cost 1,249.00 4,050.00 75.00

Total Cost (for system) 2,286.26 6,569.44 601.34

Total Cost (for system) per Mile 0.0094 0.0163 0.0042

Cab, Body and Accessories Systems Repairs (ATA VMRS 02-Cab and Sheet Metal, 50-Accessories, 71-Body)

Parts Cost 18,216.03 26,623.77 7,949.59

Labor Hours 636.1 837.4 303.5

Average Labor Cost 31,803.50 41,872.00 15,172.50

Total Cost (for system) 50,019.53 68,495.77 23,122.09

Total Cost (for system) per Mile 0.2053 0.1701 0.1612

34 Final Results Alternative Fuel Transit Buses

Breakdown of Maintenance Costs by Vehicle System (continued)

Diesel LNG LNG Control 4300 4500 Inspections Only – No Parts Replacements (101)

Parts Cost 0.00 0.00 0.00

Labor Hours 347.8 564.0 184.4

Average Labor Cost 17,387.50 28,200.00 9,217.50

Total Cost (for system) 17,387.50 28,200.00 9,217.50

Total Cost (for system) per Mile 0.0714 0.0700 0.0643

HVAC System Repairs (ATA VMRS 01)

Parts Cost 875.61 940.82 191.17

Labor Hours 88.4 133.8 10.7

Average Labor Cost 4,421.00 6,690.00 535.00

Total Cost (for system) 5,296.61 7,630.82 726.17

Total Cost (for system) per Mile 0.0217 0.0190 0.0051

Air System Repairs (ATA VMRS 10)

Parts Cost 671.46 804.23 82.25

Labor Hours 28.8 36.5 4.0

Average Labor Cost 1,437.50 1,825.00 200.00

Total Cost (for system) 2,108.96 2,629.23 282.25

Total Cost (for system) per Mile 0.0087 0.0065 0.0020

Lighting System Repairs (ATA VMRS 34)

Parts Cost 1,674.18 2,183.68 193.53

Labor Hours 132.5 137.3 25.2

Average Labor Cost 6,627.00 6,865.00 1,260.00

Total Cost (for system) 8,301.18 9,048.68 1,453.53

Total Cost (for system) per Mile 0.0341 0.0225 0.0101

Frame, Steering, and Suspension Repairs (ATA VMRS 14-Frame, 15-Steering, 16-Suspension)

Parts Cost 3,381.82 4,131.46 1,190.47

Labor Hours 71.7 32.5 15.0

Average Labor Cost 3,586.00 1,623.50 750.00

Total Cost (for system) 6,967.82 5,754.96 1,940.47

Total Cost (for system) per Mile 0.0286 0.0143 0.0135

35 Alternative Fuel Final Results Transit Buses

Breakdown of Maintenance Costs by Vehicle System (continued)

Diesel LNG LNG Control 4300 4500 Axle, Wheel, and Drive Shaft Repairs (ATA VMRS 11-Front Axle, 18-Wheels, 22-Rear Axle, 24-Drive Shaft

Parts Cost 45.59 817.50 179.21

Labor Hours 11.5 23.5 3.5

Average Labor Cost 575.00 1,172.50 175.00

Total Cost (for system) 620.59 1,990.00 354.21

Total Cost (for system) per Mile 0.0025 0.0049 0.0025

Tire Repairs (ATA VMRS 17)

Parts Cost 0.00 0.00 0.00

Labor Hours 24.8 23.3 13.0

Average Labor Cost 1,237.50 1,162.50 650.00

Total Cost (for system) 1,237.50 1,162.50 650.00

Total Cost (for system) per Mile 0.0051 0.0029 0.0045

Notes

1.The engine and fuel-related systems were chosen to include only those systems of the vehicles that could be directly affected by the selection of an alternative fuel.

2. ATA VMRS coding is based on parts that were replaced. If no part was replaced in a given repair, then the code was chosen according to the system being worked on.

3. In general, inspections (with no part replacements) were included only in the overall totals (not by sys- tem). 101 was created to track labor costs for PM inspections.

4. ATA VMRS 02-Cab and Sheet Metal represents seats, doors, etc.; ATA VMRS 50-Accessories represents fire extinguishers, test kits, etc.; ATA VMRS 71-Body represents mostly windows and windshields.

5. Average labor cost is assumed to be $50 per hour.

6. Warranty costs are not included.

7. Diesel and LNG fuel prices shown include state tax.

36 Final Results Alternative Fuel Transit Buses

Appendix B Emissions Test Results

37 Alternative Fuel Final Results Transit Buses Mile/gal BTU/mile Miles Odometer Mile/gal BTU/mile Miles Odometer Mile/gal BTU/mile Miles Odometer 2 2 2 NMHC PM CO NMHC PM CO 4 4 FIDHC CH FIDHC PM CO FIDHC CH x x x CV % 33% 34% 11% 11% 26% 7% 7% 7% 1% 24% CV % 16% 17% 11% 51% 4% 4% 4% 0% 30% St Dev 0.08 7.20 1.51 1.38 0.01 160.50 0.23 2760.24 0.02 2213 St Dev 0.70 4.43 0.13 0.16 114.55 0.17 1459.70 0.01 10835 Average 0.23 21.25 13.70 12.49 0.05 2236.10 3.32 38879.70 2.00 9150 Average 4.44 25.48 1.16 0.32 2639.40 3.85 33855.80 1.98 36600 LNG Average 0.234 21.25 13.70 12.49 0.05 e 2236.1 3.322 38879.7 1.996 9150 (LNG-diesel)/diesel -95% -17% 1081% -96% -15% -14% 15% 1% -75% Diesel Average 4.438 25.48 1.16 1.16 0.322 2639.4 3.846 33855.8 1.984 36600 3119312131243127 43243130 43213133 43293136 43283139 0.25 43203141 0.26 43223146 0.39 33.2 4323 0.15 19.9 4325 0.29 12.4 4326 0.18 23.4 11.8 4327 0.17 23.6 13.9 0.16 21.2 16.1 0.20 10.8 10.8 13.0 0.29 12.7 28.2 12.2 14.7 25.9 14.1 0.05 11.9 13.9 15.8 0.03 11.1 12.6 0.05 12.8 12.6 e 0.04 14.4 14.9 e 0.03 11.5 e 0.05 2362 11.4 e 0.05 2053 13.6 e 0.06 2573 e 0.07 3.14 2286 e 0.05 3.60 2346 e 2.87 2086 e 3.24 2244 40948 e 3.16 2099 35769 3.54 2165 44760 3.29 2147 2.02 39691 3.52 2.04 40691 3.42 2.00 36329 3.44 1.99 9600 39116 1.99 6900 36486 10500 1.99 37602 1.97 6300 37405 1.98 5300 11400 1.98 2.00 9900 9300 11600 10700 3148315231543157 42233164 4224 4222 4220 3.38 4221 4.33 4.92 26.3 5.21 24.1 4.35 23.0 21.3 1.13 32.7 1.08 1.25 1.33 1.01 0.24 0.11 2678 0.41 2620 0.54 2798 0.31 3.79 2481 3.87 2620 3.62 4.08 34327 3.87 33608 35894 1.99 31851 1.98 33599 1.99 38300 1.98 41000 1.98 17600 44300 41800 Fuel TypeFuel No. Test CO NO Test No.Test No. Vehicle CO NO No.Test No. Vehicle CO NO e – too low to be detectable with a single CBD test cycle Comparison–LNG Fueled Vehicles to Diesel Baseline Vehicles (g/mile) Vehicles to Diesel Baseline Vehicles Comparison–LNG Fueled Emissions Summary–LNG Baseline Vehicles (g/mile) Vehicles Emissions Summary–LNG Baseline (g/mile) Vehicles Emissions Summary–Diesel Baseline

38 Final Results Alternative Fuel Transit Buses

39 BUS STOP

Produced by the Center for Transportation Technologies and Systems at the National Renewable Energy Laboratory (NREL), a U.S. Department of Energy national laboratory

NREL 1617 Cole Blvd. Golden, CO 80401-3393

NREL/BR-540-28739 October 2000

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% postconsumer waste